JP2019031646A - One-pack type adhesive and fuel cell separator - Google Patents

Abstract

To provide an adhesive achieving both excellent productivity and high reliability, especially an adhesive suitable for adhesion of a fuel cell separator.SOLUTION: A one-pack type adhesive contains (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) an inorganic filler, and (E) a polycarbodiimide compound. The curing agent (B) contains at least one amine-based curing agent. The curing accelerator (C) contains at least one capsule type curing accelerator. The inorganic filler (D) contains at least one flaky inorganic filler. The content of the inorganic filler (D) is 10-200 pts.mass based on 100 pts.mass of the epoxy resin (A).SELECTED DRAWING: None

Description

  The present invention relates to a one-component adhesive and a fuel cell separator.

  Fuel cells are being developed by various companies as a next-generation clean power source. A fuel cell is configured by stacking tens to hundreds of power generation units called cells. A refrigerant for cooling the system is usually supplied between the cells to be stacked.

  The cell is configured by disposing a membrane electrode assembly (MEA) in which a positive electrode and a negative electrode are disposed on both sides of a polymer electrolyte membrane through which only hydrogen ions can pass, and a separator on the outside thereof. Hydrogen gas and oxygen gas are supplied to both sides of the MEA, respectively, and water is generated by generating electricity through reaction between hydrogen ions and oxygen that have passed through the polymer electrolyte membrane.

  The outer peripheral part of the MEA is arranged with an O-ring, a rubber sealing material or the like so that hydrogen gas and oxygen gas do not leak out of the system, thereby preventing oxygen gas and hydrogen gas from leaking out of the system. At this time, in some cases, O-ring or rubber seal material may not be sufficient to prevent gas outflow, and it is necessary to accurately stack the stacks. Therefore, separators sandwiching the MEA and electrodes, or the MEA And the separator may be bonded and integrated. In addition, since stacks of cells need to be stacked with high accuracy, the stacks may be bonded together in order to improve assembly and reduce man-hours. Since the adhesive used for these adhesions is exposed to high-temperature and high-humidity conditions during power generation of the fuel cell, high-temperature durability, heat-and-moisture resistance, and hot water resistance are required.

  In addition, in order to increase productivity, the adhesive can be cured in a short time to exhibit adhesive performance, and when the adhesive is applied by the screen printing method, the adhesive remains in the screen plate holes. In addition, the adhesive is neatly transferred to the separator that is the adherend during printing, and the transferred adhesive does not easily lose its shape. In doing so, the adhesive component does not ooze out and contaminate other than the adhesive application site, and the content of impurities (such as ions) that accelerate corrosion and shorten the life of the fuel cell is low. Is required. However, the present condition is that the adhesive which satisfy | fills the said characteristic as an adhesive agent for separators does not yet exist.

JP 2012-199204 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive that achieves both excellent productivity and high reliability, particularly an adhesive suitable for bonding a fuel cell separator.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors, as a main agent, an epoxy resin, a curing agent containing an amine curing agent, a curing accelerator containing a capsule-type curing accelerator, a scaly inorganic filler, And the one-component adhesive containing the polycarbodiimide compound was found to be excellent in printing performance such as screen printing and fast curability, and further excellent in heat and humidity resistance, thereby completing the present invention.

That is, the present invention provides the following one-pack type adhesive and fuel cell separator.
1. (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) an inorganic filler, and (E) a one-component adhesive containing a polycarbodiimide compound,
(B) The curing agent includes at least one amine-based curing agent, (C) the curing accelerator includes at least one capsule-type curing accelerator, and (D) the inorganic filler includes at least one scale. -Pack type adhesive which contains a shape-like inorganic filler and whose content of (D) inorganic filler is 10-200 mass parts with respect to 100 mass parts of (A) epoxy resin.
2. (A) The one-component adhesive whose epoxy resin is liquid at 10 degreeC.
3. (D) One or two one-component adhesives containing 5 to 100% by mass of the scaly inorganic filler in the inorganic filler.
4). (D) The one-component adhesive according to any one of 1 to 3, wherein the inorganic filler is at least one selected from talc, silica, mica and graphite.
5. The one-component adhesive according to any one of 1 to 4, wherein the amine curing agent is dicyandiamide or diaminodiphenylmethane.
6). The one-component adhesive according to any one of 1 to 5, wherein the capsule-type curing accelerator is capsule-type imidazole.
7). (C) The one-component adhesive according to any one of 1 to 6, wherein the curing accelerator includes a capsule-type curing accelerator and an imidazole compound.
8). Furthermore, (F) One-component adhesives in any one of 1-7 containing a coupling agent.
9. (F) The eight-component adhesive whose coupling agent is a silane coupling agent.
10. An adhesive for a fuel cell separator, comprising the one-component adhesive according to any one of 10.1 to 9.
11. A fuel cell separator formed by bonding a plurality of fuel cell separators using 10 fuel cell separator adhesives.
12 A fuel cell separator-MEA integrated product obtained by bonding a fuel cell separator and MEA using 10 fuel cell separator adhesives.
13. A fuel cell comprising a fuel cell separator adhered to both sides of the MEA using 10 fuel cell separator adhesives.
14. A fuel cell obtained by using the fuel cell separator adhesive according to 10.10.
15. A fuel cell comprising the fuel cell separator of 15.11.
16. A fuel cell comprising a fuel cell separator-MEA integrated product of 12.12.
17. A fuel cell comprising 13 or 14 fuel cells.
18. A method for producing a fuel cell separator, comprising: applying an adhesive for a fuel cell separator according to 18.10 to a part of the fuel cell separator; and adhering another fuel cell separator to the fuel cell separator.
19. A method for producing a fuel cell separator-MEA integrated product, comprising: applying the fuel cell separator to a part of the fuel cell separator using the adhesive for a fuel cell separator according to 19.10; and bonding the MEA.
20. 18. The method for producing a fuel cell separator according to 18 or 19, wherein the adhesive application method is a screen printing method.
The manufacturing method of a fuel cell including the process of adhere | attaching a fuel cell separator and MEA using the adhesive agent for fuel cell separators of 21.10.

  The one-component adhesive of the present invention is excellent in productivity (especially screen printability and fast curability), has high reliability, and is particularly suitable for use in bonding fuel cell separators.

[One-part adhesive]
The one-part adhesive of the present invention includes (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator including a capsule-type curing accelerator, (D) an inorganic filler including a scaly inorganic filler, And (E) a polycarbodiimide compound.

[(A) Epoxy resin]
(A) As an epoxy resin of a component, the epoxy resin generally used in the field | area of an adhesive agent can be used. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, glycidylamine type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, and naphthalene. Type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, halogenated epoxy resin and the like. Among these, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable.

  The (A) epoxy resin is preferably liquid at 10 ° C. from the viewpoint of applicability by screen printing or the like. Here, “liquid” means having fluidity, and a paste form is also included therein. Some epoxy resins that have crystallinity solidify when left at room temperature for a long period of time, but even such epoxy resins are once heated to a liquid state and then cooled and used if they are liquid at 10 ° C. be able to.

  (A) An epoxy resin may be used individually by 1 type, or may be used in combination of 2 or more type. When using 2 or more types of epoxy resins together, at least 1 type can be used if it is a liquid at 10 degreeC, and a mixture is a liquid at 10 degreeC. Moreover, a liquid epoxy resin and a solid epoxy resin can be used, for example, if they are mixed and heated at 10 ° C. in a liquid state.

  (A) In order to increase heat resistance, an epoxy resin having three or more functional groups may be used. Examples of such epoxy resins include YH434L (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.).

[(B) Curing agent]
(B) As a hardening | curing agent of a component, if it is generally used as a hardening | curing agent of an epoxy resin, it can be used, However, At least 1 sort (s) of amine-type hardening | curing agent is included. Examples of other curing agents that can be used in combination with the amine curing agent include an acid anhydride curing agent, a phenol curing agent, a Lewis acid curing agent, and a polymercaptan curing agent.

  Examples of amine curing agents include aliphatic polyamines such as diethylenetriamine, triethylenetetramine, and metaxylylenediamine, aromatic polyamines such as diaminodiphenylmethane, m-phenylenediamine, and diaminodiphenylsulfone, diethylaminopropylamine, 2,4,6- Examples include tertiary amine compounds such as tris (diaminomethyl) phenol, dicyandiamide, organic acid dihydrazide, amine adducts, and polyamine compounds such as polyamide. As the amine-based curing agent, dicyandiamide, diaminodiphenylmethane, and the like are preferable from the viewpoints of latency (storage stability as a one-part adhesive), high adhesiveness, and productivity improvement due to rapid curing.

  Examples of acid anhydride curing agents include alicyclic acid anhydrides (liquid acid anhydrides) such as hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic acid. An aromatic acid anhydride etc. are mentioned. A phenol resin etc. are mentioned as a phenol type hardening | curing agent. Examples of the Lewis acid curing agent include Lewis acids such as boron trifluoride. Examples of the polymercaptan curing agent include polysulfide, thioester, and thioether.

  (B) A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type. When using together an amine hardening | curing agent and another hardening | curing agent, it is preferable that 50 mass% or more of amine hardening agents are contained in (B) hardening | curing agent.

  (B) The hardener may be a capsule-type hardener. The capsule-type curing agent is obtained by coating the above-described curing agent with a shell such as urethane resin to form a microcapsule. As the capsule-type curing agent, a commercially available product can be used.

  (B) Content of a hardening | curing agent has the preferable quantity which becomes 0.5-1.2 equivalent with respect to the epoxy group in (A) epoxy resin in the adhesive agent of this invention, and 0.7-1.1. More preferred is an equivalent amount. Specifically, although there is a surface depending on the epoxy equivalent of the epoxy resin, the content of the (B) curing agent is preferably about 3 to 50 parts by mass with respect to 100 parts by mass of the (A) epoxy resin. About 30 mass parts is still more preferable. (B) If content of a hardening | curing agent is the said range, the characteristic as a required adhesive agent of this invention will be fully acquired.

[(C) Curing accelerator]
The curing accelerator (C) contains at least one capsule type curing accelerator. The capsule-type curing accelerator is a microencapsulated material obtained by coating a curing accelerator with a shell such as urethane resin. By dispersing this in (A) epoxy resin and making it into a master batch, a one-pack type adhesive having both high storage stability and quick curing from low temperatures can be obtained. In the present invention, a capsule type curing accelerator is used from the viewpoint of improving productivity, that is, shortening the curing time of the adhesive.

  Examples of the capsule-type curing accelerator include those encapsulating amine-based curing accelerators such as imidazole compounds and tertiary amines and salts thereof, and phosphorus-based curing accelerators such as triphenylphosphine. Specific examples of these will be described later.

  As such a capsule-type curing accelerator, commercially available products can be used, and specific examples thereof include NOVACURE (registered trademark) HX3721, HX3722, HX3748, HX3741, HX3921HP (manufactured by Asahi Kasei Corporation) and the like. It is done. These may be used alone or in combination of two or more.

  1-40 mass parts is preferable with respect to 100 mass parts of (A) epoxy resins, and, as for content of a capsule type hardening accelerator, 5-20 mass parts is more preferable. If the content of the capsule-type curing accelerator is within the above range, it is possible to achieve contamination prevention and rapid curing due to bleeding.

  (C) The curing accelerator may contain another curing accelerator in addition to the capsule-type curing accelerator. Examples of the other curing accelerator include amine-based curing accelerators such as the above-described imidazole compounds, tertiary amines and salts thereof, phosphorus-based curing accelerators, and the like, which are not encapsulated.

  Examples of the imidazole compound include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4- Methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4- Methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2 ′ -Methylimida Zolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 [2'-Ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanurate-a] benzimidazole, 1-dodecyl-2-methyl-3-benzyl-1H-imidazole-3-ium chloride, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 2-methylimidazoline, 2-phenylimidazo Emissions, and the like. Moreover, the adduct body of the imidazole compound mentioned above and an epoxy resin can also be used as the imidazole compound.

  Among these curing accelerators, among these, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)] is selected from the balance of storage stability as an adhesive and ability as a curing accelerator. -Ethyl-s-triazine (Cureazole (registered trademark) 2MZ-A: manufactured by Shikoku Chemicals Co., Ltd.) is preferred.

  When using the said other hardening accelerator together, the usage-amount is 0.1-10 mass parts with respect to 100 mass parts of epoxy resins, and 0.5-5 mass parts is more preferable. If the amount of the other curing accelerator used is within the above range, it is possible to achieve contamination prevention and rapid curing due to bleeding.

  Moreover, when using together a capsule-type hardening accelerator and another hardening accelerator, it is preferable that the said capsule-type hardening accelerator is contained 50-99 mass% in (C) hardening accelerator.

[(D) Inorganic filler]
The inorganic filler of component (D) imparts appropriate viscosity and thixotropy to the adhesive, thereby improving coating properties, particularly screen printing characteristics, and improving the mechanical strength of the adhesive.

  (D) The inorganic filler contains at least one scale-like inorganic filler from the viewpoint of improving screen printability. When scale-like inorganic fillers are used, moderate thixotropy is imparted to the adhesive, and when the adhesive is screen-printed, there is no adhesive residue in the screen holes and it is applied to the adherend (printing). There is an effect that deformation of the formed adhesive is suppressed.

  In the scale-like inorganic filler, the scale-like degree can be represented by an aspect ratio. The aspect ratio is one of the shape indices of particles represented by “average particle diameter / particle thickness”, and is measured by a flow particle image analyzer or the like. The aspect ratio of the scaly inorganic filler is preferably 5 to 200, more preferably 10 to 100, and still more preferably 20 to 60.

The average particle size of the scaly inorganic filler is preferably 0.1 to 100 μm, more preferably 1 to 50 μm, and still more preferably 2 to 15 μm. When the average particle size is in the above range, the screen printing characteristics are good. In the present invention, the average particle diameter refers to the value of the median diameter (d ₅₀ ) in the particle size distribution measurement using a laser diffraction particle size distribution meter.

  Examples of the material for the scaly filler include talc, silica (fumed silica, precipitated silica, crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrous silicic acid, etc.), mica, graphite (artificial and natural graphite) , Heavy calcium carbonate, light calcium carbonate, colloidal calcium carbonate, magnesium carbonate, clay, kaolin, aluminum hydroxide, alumina, aluminum hydroxide, barium sulfate, white carbon, E glass fine powder, titanium oxide, zirconia, silicon nitride, Examples thereof include barium titanate, barium carbonate diatomaceous earth, and carbon black. Of these, talc, silica, mica, and graphite (artificial and natural graphite) are preferable, and mica is particularly preferable. These can use a commercial item. Examples of mica include micro mica MK-100, MK-200, MK-300 (manufactured by Katakura Corp. Agri Co., Ltd.) and the like. Examples of silica include Inaflex (registered trademark) (manufactured by Nippon Sheet Glass Co., Ltd.), Sun Lovely (registered trademark) (manufactured by AGC S-Tech Co., Ltd.), and the like. Examples of graphite include CNP-7, CNP-15 (manufactured by Ito Graphite Industry Co., Ltd.), BF-7A, BF-8D, BF-10D, BF-10A (manufactured by Shinkoshi Kasei Co., Ltd.), and the like.

  Moreover, (D) inorganic filler may contain the inorganic filler which is not scale-like. At this time, the shape of the non-flaky inorganic filler is not particularly limited as long as it is not scaly, and examples thereof include a lump shape, a spherical shape, a needle shape, and an indefinite shape. Moreover, as a material of a non-flaky inorganic filler, the thing similar to what was mentioned above as a material of a flake-like filler is mentioned.

  The average particle diameter of the non-flaky inorganic filler is not particularly limited as long as the effect of the present invention is not impaired, but is preferably in the same range as the average particle diameter of the scaly inorganic filler.

  It is preferable that 5-100 mass% of scale-like inorganic fillers are contained in (D) inorganic filler.

  (D) Content of an inorganic filler is 10-200 mass parts with respect to 100 mass parts of (A) epoxy resins. (D) When the content of the inorganic filler is less than 10 parts by mass, the adhesive does not have sufficient thixotropy, so that the adhesive remains in the screen holes during screen printing or is printed (applied on the adherend). ) May flow before being bonded to the other adherend, and as a result, portions other than the original application site may be contaminated with the flowed adhesive. On the other hand, when the content exceeds 200 parts by mass, the viscosity of the adhesive becomes too high, and the handleability, workability and applicability deteriorate. (D) As for content of an inorganic filler, 30-150 mass parts is preferable.

  (D) When carbon particles (graphite or carbon black) are not used as the inorganic filler, the adhesive of the present invention has a bright color, so it is applied to a black separator formed from carbonaceous particles and a binder resin. When this is done, there is an advantage that the application state of the adhesive can be easily observed visually.

[(E) Polycarbodiimide compound]
The polycarbodiimide compound as the component (E) is a compound having a carbodiimide group (—N═C═N—), and has the effect of improving the wet heat resistance of the adhesive of the present invention. The polycarbodiimide compound can be produced, for example, by heating an organic polyisocyanate in the presence of a suitable catalyst and performing a decarboxylation reaction.

  (E) As organic polyisocyanate which is a synthesis raw material of a polycarbodiimide compound, aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate are mentioned, for example. Specifically, 1,5-naphthalene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diene Isocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2 1,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate and the like. These may be used alone or in combination of two or more.

  The decarboxylation condensation reaction of the organic polyisocyanate proceeds in the presence of a carbodiimidization catalyst. Examples of the carbodiimidization catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-1 -Phosphorene oxide such as phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide and their 3-phospholene isomers can do. Of these, 3-methyl-1-phenyl-2-phospholene-1-oxide is preferable from the viewpoint of reactivity.

  The end of the polycarbodiimide compound obtained from the organic polyisocyanate may be an isocyanate group, or may be controlled to an appropriate degree of polymerization using a compound (sealant) that reacts with the isocyanate group.

  Examples of the sealing agent include monoisocyanates such as phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate.

The sealing agent is an aliphatic compound, an aromatic compound, an alicyclic compound, such as methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether. Compounds having —OH groups such as: Compounds having ═NH groups such as diethylamine and dicyclohexylamine; Compounds having —NH ₂ groups such as butylamine and cyclohexylamine; —COOH groups such as propionic acid, benzoic acid and cyclohexanecarboxylic acid A compound having —SH group such as ethyl mercaptan, allyl mercaptan, thiophenol, or a compound having an epoxy group can be used.

  (E) The polycarbodiimide compound has a number average molecular weight (Mn) of preferably 500 to 8,000, and more preferably 1,000 to 5,000. If Mn is the said range, since the heat resistance and handleability of a polycarbodiimide compound are favorable, it is preferable. In the present invention, Mn is a measured value in terms of polystyrene measured by gel permeation chromatography (GPC).

  (E) The polycarbodiimide compound is preferably a liquid in a bulk state (a state without a solvent). Commercially available products can be used as the polycarbodiimide compound, and specific examples thereof include Carbodilite (registered trademark) V-05, V-02B (manufactured by Nisshinbo Chemical Co., Ltd.) and the like.

  (E) 0.5-10 mass parts is preferable with respect to 100 mass parts of (A) epoxy resins, and, as for content of a polycarbodiimide compound, 2-5 mass parts is more preferable. (E) If content of a polycarbodiimide compound is the said range, sufficient heat-and-moisture resistance will be obtained.

[(F) Coupling agent]
The one-component adhesive of the present invention may contain a coupling agent as the component (F) in addition to the components (A) to (E). (F) A coupling agent has the effect | action which improves the wettability to the resin of an inorganic filler, and raises the adhesive force of an adhesive agent. Examples of the coupling agent include a silane coupling agent, a titania coupling agent, and an aluminum chelate compound.

  Examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and other epoxy silanes, γ-aminopropyl. Triethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-ureidopropyl Aminosilanes such as triethoxysilane, mercaptosilanes such as 3-mercaptopropyltrimethoxysilane, p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ −Me Vinyl silanes such as tacryloxypropyltrimethoxysilane, epoxy-type, amino-type, and vinyl-type polymer silanes can be used, and epoxy silane, amino silane, and mercapto silane are particularly preferable. Examples of commercially available products include KBM-403, KBE-903, KBM-802 (manufactured by Shin-Etsu Chemical Co., Ltd.), Z-6040, Z-6011, and Z-6062 (manufactured by Toray Dow Corning Co., Ltd.).

  Examples of titania coupling agents include isopropyl triisostearoyl titanate, isopropyl tri (N-aminoethyl / aminoethyl) titanate, diisopropyl bis (dioctyl phosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditritriol). Decyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate .

  The aluminum chelate compound is obtained by substituting a part or all of the alkoxide of the aluminum alkoxide with a chelating agent such as alkyl acetoacetate or acetylacetone. Specific examples thereof include aluminum ethyl acetoacetate diisopropylate, aluminum tris (ethyl acetoacetate), aluminum tris (acetylacetonate), aluminum bisethylacetoacetate monoacetylacetonate and the like.

  As a method of using the coupling agent, the surface treatment of the inorganic filler may be performed in advance by a known method such as a wet method or a dry method, and when other organic / inorganic raw materials are added, they are added together. May be used.

  (F) As for content of a coupling agent, 0.5-2 mass parts is preferable with respect to 100 mass parts of (D) inorganic fillers. If it is the said range, the effect of the coupling agent mentioned above will fully be acquired.

[Other ingredients]
The one-component liquid adhesive of the present invention is a colorant (for example, carbon black, dye, etc.), a flame retardant, an ion trap agent, an antifoaming agent, and a leveling agent as necessary, as long as the effects of the present invention are not impaired. Etc. may be included. Furthermore, an epoxy resin having one epoxy group in one molecule called a so-called reactive diluent and having a low viscosity can be used as long as the effect of the present invention is not impaired. The one-part liquid adhesive of the present invention may contain a solvent for viscosity adjustment, but if it contains a solvent, it may volatilize and cause a gas leak when the resin is cured. Preferably there is.

[Method for preparing one-pack adhesive]
The one-component adhesive of the present invention can be adjusted by stirring and mixing the above-described raw materials by a known method. Stirring and mixing can be performed using, for example, various mixers such as a dissolver, homogenizer, and homodisper, a kneader, a roll mill, a bead mill, a planetary mixer, a universal stirrer, a self-revolving stirrer, a planetary stirrer, and the like. Further, after stirring and mixing, defoaming may be performed under vacuum.

  If a strong shearing force is applied to the scale-like inorganic filler, the scale state may be destroyed and good screen printability may not be exhibited. Therefore, when mixing the inorganic filler, a planetary mixer, a universal stirrer, The use of a revolving stirrer or a planetary stirrer is preferred.

  Similarly, if a strong shearing force is applied to the capsule-type curing accelerator, the capsule may be destroyed and the curing reaction may proceed during mixing. When mixing the capsule-type curing accelerator, a planetary mixer or a universal agitator is used. It is preferable to use a self-revolving stirrer or a planetary stirrer.

  On the other hand, when mixing components other than the scaly inorganic filler and the capsule-type curing accelerator, it is preferable to use a roll mill or a bead mill in order to apply a strong shearing force and uniformly disperse.

[Use of one-component adhesives]
The one-part adhesive of the present invention is suitable as an adhesive for a polymer electrolyte fuel cell, and particularly suitable as an adhesive for a fuel cell separator. As the fuel cell separator, a carbon separator is preferable. The carbon separator is obtained by molding a composition containing a carbon material and a binder resin. The carbon material and the binder resin are not particularly limited, and conventionally known ones can be used. Examples of the carbon material include natural graphite, graphite powder of artificial graphite, coal-based pitch, petroleum-based pitch, coke, activated carbon, glassy carbon, acetylene black, ketjen black, and the like. In addition, as the binder resin, epoxy resin, phenol resin, polyester resin, acrylic resin, melamine resin, polyamide resin, polyimide resin, polyamideimide resin, polyetherimide resin, phenoxy resin, urea resin, melamine resin, silicone resin, Examples include vinyl ester resins, diallyl phthalate resins, and benzoxazine resins.

[Fuel cell separator]
The fuel cell separator of the present invention is manufactured using the one-component adhesive, and specifically, manufactured by bonding a plurality of separators using the one-component adhesive. It is. As a manufacturing method of the fuel cell separator of the present invention, for example, the one-component adhesive is applied to a part of the separator (for example, the outer peripheral portion) by an arbitrary method, the other separators are stacked, pressure-bonded, and heated. And bonding them.

  The pressure at the time of pressure bonding is preferably about 0.001 to 7 MPa, and more preferably about 0.02 to 4 MPa. As heating temperature, about 130-220 degreeC is preferable and about 150-200 degreeC is more preferable. Further, the heating time for pressure bonding is preferably about 0.5 to 60 minutes, and more preferably about 1 to 30 minutes.

  The method for applying the one-component adhesive of the present invention is not particularly limited, and examples include screen printing, dispenser, roll coater, gravure printing, spray coating, etc., but screen printing is preferable from the viewpoint of productivity. . The one-component adhesive of the present invention can prevent the adhesive from remaining on the screen plate during screen printing and can perform high-speed printing. At this time, it is preferable to apply so that the thickness of the adhesive layer is 50 to 500 μm, and it is more preferable to apply so that the thickness is 100 to 400 μm.

  When the separators are bonded using the one-component adhesive of the present invention, the separator cooling surfaces may be bonded to each other by applying to a part (for example, the outer periphery) of the separator cooling surfaces. You may apply | coat to a part (for example, outer peripheral part) of a surface, and may adhere the reaction surfaces of a separator. When the separators are applied to the reaction surfaces of the separators, the MEAs may be sandwiched and adhered without touching the part where the adhesive is applied.

[Fuel cell separator-MEA integrated product]
In addition, the one-component adhesive of the present invention can be suitably used for bonding a separator and MEA. For example, the one-component adhesive may be applied to a part of the separator (for example, the outer peripheral portion) by an arbitrary method, the MEAs may be stacked, pressure-bonded, and heated to be bonded. At this time, the method for applying the adhesive and the pressure heating conditions may be the same as those described in the method for bonding the fuel cell separators. In this manner, a fuel cell separator-MEA integrated product in which the fuel cell separator and the MEA are bonded with the adhesive of the present invention can be manufactured.

[Fuel battery cell]
The fuel cell of the present invention is obtained by adhering a fuel cell separator to both sides of the MEA using the one-component adhesive. As the method, for example, the one-part adhesive is applied by any method in the vicinity of the outer peripheral portion of the surface of the separator in contact with the MEA, and the two separators are overlapped with each other with the MEA interposed therebetween, followed by pressure bonding. A method of heating and bonding is mentioned. At this time, the method for applying the adhesive and the pressure heating condition may be the same as those described in the method for bonding the fuel cell separators.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example. In addition, the reagent used in the following example is as follows.

(A) Epoxy resin (A-1) YD-8125: Bisphenol A type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
(A-2) EPICLON (registered trademark) EXA835LV: Bisphenol A / F mixed epoxy resin (manufactured by DIC Corporation)
(A-3) YH434L: Glycidylamine type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
(A-4) EPICLON N-740: Phenol novolac type epoxy resin (manufactured by DIC Corporation)

(B) Curing agent (B-1) jER Cure (registered trademark) DICY7: Dicyandiamide (manufactured by Mitsubishi Chemical Corporation)
(B-2) Diaminodiphenylmethane (manufactured by Tokyo Chemical Industry Co., Ltd.)
(B-3) EPICLON B-570H: Methyltetrahydrophthalic anhydride (manufactured by DIC Corporation)

(C) Curing accelerator (C-1) Curezol 2MZ-A: Imidazole-based curing accelerator (manufactured by Shikoku Chemicals Co., Ltd.)
(C-2) Novacure HX3722: Capsule type curing accelerator (Asahi Kasei Corporation)

(D) Inorganic filler (D-1) MK-100: Mica (manufactured by Katakura Corp. Agri Co., Ltd., average particle size 5 μm, scaly, aspect ratio 30 to 50)
(D-2) Ainaflex (registered trademark): silica (manufactured by Nippon Sheet Glass Co., Ltd., average particle size 10 μm, scaly, aspect ratio 10)
(D-3) BF-10A: Graphite (manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 10 μm, scaly, aspect ratio 10)
(D-4) SA31: Alumina powder (manufactured by Nippon Light Metal Co., Ltd., average particle size 5 μm, lump)
(D-5) FB940: Silica (Denka Co., Ltd., average particle size 15 μm, spherical)

(E) Polycarbodiimide (E-1) Carbodilite V-05; Polycarbodiimide compound (Nisshinbo Chemical Co., Ltd.)

(F) Coupling agent (F-1) KBM403: Epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)
(F-2) KBE903: Amino group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)

[1] Preparation of fuel cell separator sample Artificial graphite powder (average particle size: 100 μm at particle size distribution d ₅₀ ) 100 parts by mass, o-cresol novolac type epoxy resin (epoxy equivalent: 204 g / eq, ICI viscosity at 150 ° C. 0) .65 Pa · s) 20.5 parts by mass, novolak-type phenolic resin (hydroxy group equivalent: 103 g / eq, ICI viscosity at 150 ° C. 0.22 Pa · s) 10.5 parts by mass, and 2-phenylimidazole 0.3 A binder component consisting of parts by mass and 0.2 part by mass of carnauba wax as an internal release agent were put into a Henschel mixer and mixed at 800 rpm for 3 minutes to prepare a composition for a fuel cell separator.
The obtained composition was put into a mold for producing a fuel cell separator having a size of 200 mm × 200 mm, press-molded under conditions of a mold temperature of 185 ° C., a molding pressure of 30 MPa, a molding time of 30 seconds, and a groove serving as a gas channel was formed. A fuel cell separator preform formed on one side was obtained.
Alumina polishing material (average particle size: 6 μm in particle size distribution d ₅₀ ) is used on both surfaces (gas flow channel surface and the opposite surface) of the obtained preform, and the discharge pressure is 0.22 MPa. A roughening treatment was performed by wet blasting to obtain a fuel cell separator sample.

[2] Preparation of adhesive [Example 1]
After roughly mixing 70 parts by mass of epoxy resin (A-1), 30 parts by mass of epoxy resin (A-3), 6 parts by mass of curing agent (B-1) and 3 parts by mass of curing accelerator (C-1), Passed through a 3 roll mill. To the obtained mixture, 10 parts by mass of a curing accelerator (C-2), 100 parts by mass of an inorganic filler (D-1), 3 parts by mass of a polycarbodiimide compound (E-1), and a silane coupling agent (E -1) 1 part by mass was added and mixed for 3 minutes using a planetary stirring and defoaming device (Mazerustar KK-400W manufactured by Kurashiki Boseki Co., Ltd.) to obtain a light yellow paste-like adhesive.

[Examples 2 to 8, Comparative Examples 1 to 6]
According to the composition shown in Table 1 below, an adhesive was prepared in the same manner as in Example 1.

[3] Adhesive evaluation (1) Screen printability Using a screen printer (semi-automatic screen printer manufactured by Ceria Corporation), using a 80 mesh screen (210 μm aperture), squeegee load 30 kg, squeegee After printing the adhesives prepared in Examples 1-8 and Comparative Examples 1-6 on a fuel cell separator sample (120 mm × 120 mm) at a speed of 50 mm / sec, the presence or absence of residual adhesive in the holes of the screen used was checked. It was observed visually.
The criteria for determining screen printability are as follows.
No adhesive remains in the screen holes after printing ... G
Adhesive remains in the screen holes after printing ... N

(2) Fast Curability The adhesives prepared in Examples 1 to 8 and Comparative Examples 1 to 6 were heated in a dryer at 180 ° C. for 1 minute, and then taken out from the dryer and a differential scanning calorimeter (Seiko). The presence or absence of an exothermic peak was observed under the condition of a temperature rising rate of 10 ° C./min.
The criteria for determining fast curability are as follows.
No exothermic peak ... G
There is an exothermic peak ... N
The exothermic peak represents the curing reaction of the adhesive, and indicates that the curing was insufficient under the conditions of 180 ° C. and 1 minute.

(3) Breathability After the adhesives prepared in Examples 1-8 and Comparative Examples 1-6 were printed on fuel cell separator samples (120 mm × 120 mm) in the same manner as described in the screen printability, Other separators were superposed on the printing surface and heated at 150 ° C. for 30 minutes under a load of 1 MPa in a dryer to prepare an adhesive separator sample. After taking out from the dryer, the bleeding of the adhesive on the part where the adhesive was printed was visually observed.
The criteria for the bleeding property are as follows.
Adhesive does not ooze out of the adhesive printing part ... G
Adhesive oozes out of the adhesive printing part ... N

(4) Moisture and heat resistance The adhesives prepared in Examples 1 to 8 and Comparative Examples 1 to 6 were heated at 150 ° C. for 30 minutes in a dryer to be completely cured to obtain a cured adhesive of 4 mm × 18 mm × 2 mm. It was. The glass transition temperature (Tg) of the cured adhesive was measured using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.). The glass transition temperature (Tg) is measured under the condition of a heating rate of 3 ° C./min while applying a tensile load at which the sample is distorted by 10 μm at a frequency of 1 Hz, and the obtained two kinds of elastic modulus (loss elastic modulus, storage elastic modulus). ) Is a glass transition temperature (Tg) that gives the maximum value of the ratio tan δ (= loss elastic modulus / storage elastic modulus). Further, the cured adhesive was stored under the following wet heat conditions.
Condition 1: Immersion in warm water at 80 ° C. for 2,000 hours Condition 2: In a warm water / ethylene glycol mixture (mixing ratio 1-1) at 80 ° C.
Immersion for 2,000 hours The criteria for determination of moisture and heat resistance are as follows.
The glass transition temperature (Tg) after immersion for both conditions 1 and 2 is 90 ° C or higher.
The glass transition temperature (Tg) after immersion of at least one of Condition 1 and Condition 2 is 90 ° C. or lower N

(5) Gas leak test (room temperature)
The presence or absence of air leakage was confirmed by flowing 0.1 MPa of air inside the bonded portion of the adhesive separator sample produced by the same method as the bleeding.
The criteria for the gas leak test (room temperature) are as follows.
No air leak G
Air leaks ... N

(6) Gas leak test (after immersion in hot water)
After immersing the adhesive separator sample produced by the same method as the bleeding property in 90 ° C. warm water for 2,000 hours, 0.1 MPa of air was allowed to flow inside the adhesive part of the adhesive separator sample to prevent air leakage. The presence or absence was confirmed.
The criteria for the gas leak test (after immersion in hot water) are as follows.
No air leak G
Air leaks ... N

  These evaluation results are also shown in Table 1.

  From the results shown in Table 1, according to the present invention, it is excellent in productivity (screen printability, fast curability), wet heat resistance, and highly reliable one-part adhesive, particularly for fuel cell separators. It becomes possible to provide a suitable one-component adhesive.

Claims (21)

(A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) an inorganic filler, and (E) a one-component adhesive containing a polycarbodiimide compound,
(B) The curing agent includes at least one amine-based curing agent, (C) the curing accelerator includes at least one capsule-type curing accelerator, and (D) the inorganic filler includes at least one scale. -Pack type adhesive which contains a shape-like inorganic filler and whose content of (D) inorganic filler is 10-200 mass parts with respect to 100 mass parts of (A) epoxy resin.   The one-component adhesive according to claim 1, wherein (A) the epoxy resin is liquid at 10 ° C.   (D) The one-component adhesive according to claim 1 or 2, wherein 5 to 100% by mass of the scaly inorganic filler is contained in the inorganic filler.   (D) The one-component adhesive according to any one of claims 1 to 3, wherein the inorganic filler is at least one selected from talc, silica, mica and graphite.   The one-component adhesive according to any one of claims 1 to 4, wherein the amine-based curing agent is dicyandiamide or diaminodiphenylmethane.   The one-component adhesive according to any one of claims 1 to 5, wherein the capsule-type curing accelerator is a capsule-type imidazole.   (C) The one-component adhesive according to any one of claims 1 to 6, wherein the curing accelerator comprises a capsule-type curing accelerator and an imidazole compound.   The one-component adhesive according to any one of claims 1 to 7, further comprising (F) a coupling agent.   The one-component adhesive according to claim 8, wherein the coupling agent is a silane coupling agent.   The adhesive for fuel cell separators which consists of a one-component adhesive agent of any one of Claims 1-9.   A fuel cell separator obtained by bonding a plurality of fuel cell separators using the fuel cell separator adhesive according to claim 10.   A fuel cell separator-membrane electrode assembly integrated product obtained by bonding a fuel cell separator and a membrane electrode assembly using the fuel cell separator adhesive according to claim 10.   A fuel battery cell comprising a fuel cell separator bonded to both sides of the membrane electrode assembly using the fuel cell separator adhesive according to claim 10.   A fuel cell obtained by using the adhesive for a fuel cell separator according to claim 10.   A fuel cell comprising the fuel cell separator according to claim 11.   A fuel cell comprising the fuel cell separator-membrane electrode assembly integrated product according to claim 12.   A fuel cell comprising the fuel cell according to claim 13 or 14.   A method for producing a fuel cell separator, comprising: applying the fuel cell separator adhesive according to claim 10 to a part of the fuel cell separator; and adhering another fuel cell separator to the fuel cell separator.   Manufacturing of a fuel cell separator-membrane electrode assembly integrated product comprising a step of applying the fuel cell separator adhesive according to claim 10 to a part of the fuel cell separator and a step of bonding the membrane electrode assembly. Method.   The method for producing a fuel cell separator according to claim 18 or 19, wherein the adhesive application method is a screen printing method.   The manufacturing method of a fuel cell including the process of adhere | attaching a fuel cell separator and a membrane electrode assembly using the adhesive for fuel cell separators of Claim 10.